Non-linear Vibration And Noise Analysis And Dynamic Optimization Of Double-ring Reducer

Because of the advantages, such as small size, light weight, long life, high loading capacity, high transmitting efficiency, etc., gear system has been widely used in national defense and civil industry. With the improvement of equipment manufacturing technology, the gearboxes are turning to be large-size, high-speed, light-weight, high-precision and automatic devices and the requirements of gear noise become much higher. Therefore the research on vibration noise and dynamic optimization of gear device has important theory significance and great engineering values on vibration and noise reduction.The project of this thesis is supported by National Key Technology R&D Program of China and Natural Science Foundation of Chongqing. With theories of dynamics, acoustics and optimization design and methods of FEM and BEM, the nonlinear analysis of vibration noise and dynamic optimization of the double-ring gear reducer have been carried out in this paper. The main research work in this paper can be summarized as follows:1) The parametric finite element analysis modal of the double-ring gear reducer is established with ANSYS Parametric Design Language (APDL). After the finite element modal analysis of the gearbox housing and gear system being done separately with the method of block Lanczos, the natural frequency and normal mode of the reducer are obtained.2) The internal dynamic excitation produced by stiffness excitation, error excitation and mesh impact excitation is simulated at first with finite element method. Then apply this excitation got before on the meshing lines of gears. After the transient response of the double-ring gear reducer being calculated with ANSYS software, the vibration displacements, vibration velocities and vibration accelerations of reducer are obtained, then compared with the test results.3) Consider the structure parameters of the reducer housing as design variables, and displacement and static strength as the state variables to establish the dynamic response optimization model of the double-ring gear reducer. Then do the multi-frequency modal optimization of the gearbox to avoid the natural frequencies from the tooth-mesh frequency. Taking the RMS value of vibration acceleration of the housing as the objective function, a best design sets can be obtained with first order optimization method.4) Taking the frequency-domain responses of surface nodes on the gear reducer as boundary conditions, the acoustic boundary element model of the housing is established with the direct boundary element method of the SYSNOISE software to calculate the acoustic pressure of the gearbox surface and the radiation noise of outer field points. The A-weighted octave radiation noise is tested to be compared with the simulation results. And it shows that the two agree well.